[PATCH v2 1/2] fuse: use default writeback accounting

[Joanne Koong <joannelkoong@gmail.com>]

commit 0c58a97f919c ("fuse: remove tmp folio for writebacks and internal
rb tree") removed temp folios for dirty page writeback. Consequently,
fuse can now use the default writeback accounting.

With switching fuse to use default writeback accounting, there are some
added benefits. This updates wb->writeback_inodes tracking as well now
and updates writeback throughput estimates after writeback completion.

This commit also removes inc_wb_stat() and dec_wb_stat(). These have no
callers anymore now that fuse does not call them.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 fs/fuse/file.c              |  9 +--------
 fs/fuse/inode.c             |  2 --
 include/linux/backing-dev.h | 10 ----------
 3 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index adc4aa6810f5..e53331c851eb 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1784,19 +1784,15 @@ static void fuse_writepage_finish(struct fuse_writepage_args *wpa)
 	struct fuse_args_pages *ap = &wpa->ia.ap;
 	struct inode *inode = wpa->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	int i;
 
-	for (i = 0; i < ap->num_folios; i++) {
+	for (i = 0; i < ap->num_folios; i++)
 		/*
 		 * Benchmarks showed that ending writeback within the
 		 * scope of the fi->lock alleviates xarray lock
 		 * contention and noticeably improves performance.
 		 */
 		folio_end_writeback(ap->folios[i]);
-		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
-		wb_writeout_inc(&bdi->wb);
-	}
 
 	wake_up(&fi->page_waitq);
 }
@@ -1982,14 +1978,11 @@ static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
 static void fuse_writepage_args_page_fill(struct fuse_writepage_args *wpa, struct folio *folio,
 					  uint32_t folio_index)
 {
-	struct inode *inode = folio->mapping->host;
 	struct fuse_args_pages *ap = &wpa->ia.ap;
 
 	ap->folios[folio_index] = folio;
 	ap->descs[folio_index].offset = 0;
 	ap->descs[folio_index].length = folio_size(folio);
-
-	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
 }
 
 static struct fuse_writepage_args *fuse_writepage_args_setup(struct folio *folio,
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index bfe8d8af46f3..a6c064eb7d08 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1557,8 +1557,6 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	if (err)
 		return err;
 
-	/* fuse does it's own writeback accounting */
-	sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
 	sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
 
 	/*
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e721148c95d0..9a1e895dd5df 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -66,16 +66,6 @@ static inline void wb_stat_mod(struct bdi_writeback *wb,
 	percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH);
 }
 
-static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
-{
-	wb_stat_mod(wb, item, 1);
-}
-
-static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
-{
-	wb_stat_mod(wb, item, -1);
-}
-
 static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 {
 	return percpu_counter_read_positive(&wb->stat[item]);
-- 
2.47.1